Comments on: Natural Variation vs Human Influence

By: cohenite

cohenite — Mon, 26 Oct 2009 10:05:41 +0000

Nick, you've verballed me; you raised the date of 1950 first in your initial comment; your CO2 graphs are also misleading in the usual way; fig's 5 & 6 here explain why;

http://brneurosci.org/co2.html

although to be honest I like Roy Spencer's version;

http://www.drroyspencer.com/2009/01/50-years-of...

By: davids99us

davids99us — Mon, 26 Oct 2009 09:21:02 +0000

Its just a mystery

By: Nick Stokes

Nick Stokes — Mon, 26 Oct 2009 02:11:39 +0000

No, that's the point. It's the lower frequency (longer cycle) that generates the harmonics (frequency multiples).

By: Andrew

Andrew — Mon, 26 Oct 2009 00:27:40 +0000

“The 63 year “natural” period, is highly speculative”

It is the only theory so far which explains the 1911-1941 warming occurring at the same rate as the 1978-2008 warming.

By: sherro

sherro — Mon, 26 Oct 2009 00:12:23 +0000

Nick, If you can dissect a compound curve into a series of less complicated ones, using Occam's Razor type reasoning (which I do not rely upon, but it's short hand for what I mean), then you have some material to which you can start to ascribe causes. Sure, there is a probability that your dissection means nothing in physical terms, there is a possibility that it's a mathematical artefact.

However, when a number of different measurement techniques start to show repeated similarity to one or more of the sub-curves, you can start to form a hypothesis, then proceed through the scientific method with that hypothesis. An example might involve the orbital variation in Earth-Sun distance over time. A reasonable start would assume that a greater separation produces less irradiance at the Earth. So you quantify it and subtract it from the original compound curve. Then you proceed with successive stripping steps until you get a good fit, being careful to ensure the carrying of error terms as you go.

Where we differ is in the assumption that the GHG effect is a given and can be confidently stripped out first. The difficulty is that its effect is a guesstimate, it is not robust.

You answered your own thoughts by writing "...if David wants to claim that that says something about natural vs anthropogenic, those connections have to be made." The answer is, "If Nick wants to claim.....etc". The jury is still out on GHG, Nick.

BTW, what I think about the shape of a curve back to 1880 is immaterial. A method to determine the parameters of such a curve is material. Science is not about what you think, it's about what you can demonstrate to a tough audience.

This also applies to GISSTEMP, of which you write "If you fit GISStemp alone with a line you get about 0.06 C/decade, as is well-known. " It is well-known because of publicity, not because it is right. One can drive a truck through the errors in GISSTEMP, as has been done several times.

By: Andrew

Andrew — Sun, 25 Oct 2009 23:52:05 +0000

A master of disingenuous-ness, I see. Scafetta did no analysis of those other recons. and what can be said of many of them? Why, that Mann or Mann coauthors are authors, and that they use many of the same proxies!

http://www.climateaudit.org/pdf/others/07142006...

Figures 5.2 through 5.8

NOTE THAT A RESPONSE WHICH DOES NOT COMMENT ON THESE FIGURES IN PARTICULAR WILL BE IGNORED.

By: davids99us

davids99us — Sun, 25 Oct 2009 23:47:00 +0000

Exactly, a resonant frequency seen in AMO and PDO driven by absorbed energy
from a shorter Hale cycle.

By: Nick Stokes

Nick Stokes — Sun, 25 Oct 2009 23:28:38 +0000

Integer multiples of frequencies might suggest harmonics.

Mostly people associate the 63 year period with ocean effects.

By: Nick Stokes

Nick Stokes — Sun, 25 Oct 2009 23:26:34 +0000

"So your argument is that the results are uncertain because Mann might be right?"
No. Scafetta is saying that on some data, you get nothing, on others, some solar component. And the nothing data includes not just Mann, but many others.

By: Nick Stokes

Nick Stokes — Sun, 25 Oct 2009 23:24:51 +0000

Why you insist on going back to 1950 I don't know.
Because that's what Coho said (and David in the OP), to which I'm responding.